From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 123F3391E59; Fri, 12 Jun 2026 13:37:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781271469; cv=none; b=X6URqouZNOz05XOwUV1Ttsmj1/0syn6XShImS2ldzR7pulikpp7wRTA+lOUk93/G6tFwgf1jmDoEVcHVC4I0swf8oUPhOaTWwNur7UXIZ9RXbMqPgSAx60HyIuXxXWmd9VrDWAbuPByQ0mnXoJ/V4cVeGmpXQ8EZlq1dEvaCOEY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781271469; c=relaxed/simple; bh=8xHaDodoBZCC7iQjVFkUhno452EbTk8XS34uSq81f9M=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=QTJSiSvD8t1ph7q/l8oontgaNet1PVOQTwlUNR6wbB8VWS55aO75zqZ2tHyHAuMP83vKxmPvBuUDzWFLzykrNoOpuioW31Fq4mfkprrVsWB1h3Dj02BRyTBEcG7EBN9gEwkoU2q7raxYmWiz6+APOYcNrhoJa94hnoKlAKwCNWg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GO8wQA5Q; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="GO8wQA5Q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 455261F00A3A; Fri, 12 Jun 2026 13:37:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781271468; bh=8tol5F4Al0rEBV8usRwIGeeY4X/HKey0W2n0cxj983U=; h=Subject:From:To:Cc:Date:In-Reply-To:References; b=GO8wQA5QzHZLTtGPodC69jnfdWZxVcrA0e5y+4JYe0HHG9eMxYTSIudFlTgXHKITh YU4gWmuv9pyJNpcMoSHrC3uw6YplGQ7KM9iYSnRWEnmzgl4RAdoNnsTR3lVRP8OE0J 9lJ8wtHVdyqYPeG/FUxTPMBpK1muQEPks0Dt1pa7PrH4oi3dAXHLRZWuI63a0mB+R3 U/exZU9lktUw69y/DtgyVv36CqFvEqX8oBVgMzRgHVjp4pimKx52wc3pSzugVoUtwf scXBoeevv6cn9WWyffB4GYQ2Uk/zVWmQ5b6FUQDuOGTfy+ur0UA4CyHixP8CgNDJ/E mtBPsJnHZ874w== Message-ID: <296694ccd427fec43eabebd10f56c0b0d5ad9a45.camel@kernel.org> Subject: Re: [PATCH v2 15/21] nfsd: validate sockaddr length per family in listener_set From: Jeff Layton To: Chuck Lever , NeilBrown , Olga Kornievskaia , Dai Ngo , Tom Talpey Cc: Chris Mason , linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org Date: Fri, 12 Jun 2026 09:37:45 -0400 In-Reply-To: <20260611-nfsd-testing-v2-15-5b90e276f2d9@kernel.org> References: <20260611-nfsd-testing-v2-0-5b90e276f2d9@kernel.org> <20260611-nfsd-testing-v2-15-5b90e276f2d9@kernel.org> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv egyjnSsFt7EGoDjdKqr1TS9syJYFjagYtvWk/UfHlW09X+jOh4vYtfX7iYSx/NfqV3W1D7EDi0PqV 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Thu, 2026-06-11 at 16:00 -0400, Jeff Layton wrote: > nfsd_sock_nl_policy declares NFSD_A_SOCK_ADDR as bare NLA_BINARY > with no minimum length. A CAP_NET_ADMIN caller can send a 16-byte > NFSD_A_SOCK_ADDR with sa_family=3DAF_INET6, causing a 12-byte OOB > read across three consumers (rpc_cmp_addr_port, svc_find_listener, > kernel_bind). >=20 > Tighten the policy to NLA_POLICY_MIN_LEN(16) and add per-family > length validation in both nlmsg_for_each_attr_type loops. >=20 > Fixes: 16a471177496 ("NFSD: add listener-{set,get} netlink command") > Assisted-by: Claude:claude-opus-4-8 > Signed-off-by: Jeff Layton > --- > Documentation/netlink/specs/nfsd.yaml | 4 ++++ > fs/nfsd/netlink.c | 2 +- > fs/nfsd/nfsctl.c | 30 +++++++++++++++++++++++++++++= + > 3 files changed, 35 insertions(+), 1 deletion(-) >=20 > diff --git a/Documentation/netlink/specs/nfsd.yaml b/Documentation/netlin= k/specs/nfsd.yaml > index 8f36fadd68f7..9677ba19ffcd 100644 > --- a/Documentation/netlink/specs/nfsd.yaml > +++ b/Documentation/netlink/specs/nfsd.yaml > @@ -156,6 +156,10 @@ attribute-sets: > - > name: addr > type: binary > + # 16 =3D=3D sizeof(struct sockaddr_in); AF_INET6 callers > + # validate the full sockaddr_in6 length in nfsctl.c. > + checks: > + min-len: 16 > - > name: transport-name > type: string > diff --git a/fs/nfsd/netlink.c b/fs/nfsd/netlink.c > index fbee3676d253..6570960034f1 100644 > --- a/fs/nfsd/netlink.c > +++ b/fs/nfsd/netlink.c > @@ -37,7 +37,7 @@ const struct nla_policy nfsd_fslocations_nl_policy[NFSD= _A_FSLOCATIONS_LOCATION + > }; > =20 > const struct nla_policy nfsd_sock_nl_policy[NFSD_A_SOCK_TRANSPORT_NAME += 1] =3D { > - [NFSD_A_SOCK_ADDR] =3D { .type =3D NLA_BINARY, }, > + [NFSD_A_SOCK_ADDR] =3D NLA_POLICY_MIN_LEN(16), > [NFSD_A_SOCK_TRANSPORT_NAME] =3D { .type =3D NLA_NUL_STRING, }, > }; > =20 > diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c > index ab10692ee937..f3b3154b16c5 100644 > --- a/fs/nfsd/nfsctl.c > +++ b/fs/nfsd/nfsctl.c > @@ -2016,6 +2016,21 @@ int nfsd_nl_listener_set_doit(struct sk_buff *skb,= struct genl_info *info) > xcl_name =3D nla_data(tb[NFSD_A_SOCK_TRANSPORT_NAME]); > sa =3D nla_data(tb[NFSD_A_SOCK_ADDR]); > =20 > + switch (sa->sa_family) { > + case AF_INET: > + if (nla_len(tb[NFSD_A_SOCK_ADDR]) < > + sizeof(struct sockaddr_in)) > + continue; > + break; > + case AF_INET6: > + if (nla_len(tb[NFSD_A_SOCK_ADDR]) < > + sizeof(struct sockaddr_in6)) > + continue; > + break; > + default: > + continue; > + } > + > /* Put back any matching sockets */ > list_for_each_entry_safe(xprt, tmp, &permsocks, xpt_list) { > /* This shouldn't be possible */ > @@ -2077,6 +2092,21 @@ int nfsd_nl_listener_set_doit(struct sk_buff *skb,= struct genl_info *info) > xcl_name =3D nla_data(tb[NFSD_A_SOCK_TRANSPORT_NAME]); > sa =3D nla_data(tb[NFSD_A_SOCK_ADDR]); > =20 > + switch (sa->sa_family) { > + case AF_INET: > + if (nla_len(tb[NFSD_A_SOCK_ADDR]) < > + sizeof(struct sockaddr_in)) > + continue; > + break; > + case AF_INET6: > + if (nla_len(tb[NFSD_A_SOCK_ADDR]) < > + sizeof(struct sockaddr_in6)) > + continue; > + break; > + default: > + continue; > + } > + Sashiko flagged a problem above that we should probably fix. If we get an invalid address here, we should return an error instead of ignoring it. I'm working on an updated patch now. > xprt =3D svc_find_listener(serv, xcl_name, net, sa); > if (xprt) { > if (delete) --=20 Jeff Layton